One week of MSE: 1.5 million downloads, 4 million detections

Microsoft Security Essentials data for the first week has been released, and …

Redmond has released data from the first week (between September 29 to October 6) of Microsoft Security Essentials (MSE) usage, the company's free, real-time consumer antimalware solution for fighting viruses, spyware, rootkits, and Trojans. The product was made generally available to consumers in 19 countries in eight languages, and in the first week Microsoft says it has seen well over 1.5 million downloads. "By the end of week two, we had exceeded 2.6 million downloads," a Microsoft spokesperson told Ars. Number of downloads is never equivalent to the number of installs though: the software giant can't say how many machines have the software installed, but it can weigh in on the number of infected machines.

Microsoft says that in the first week, MSE made almost four million detections on 535,752 distinct machines; the company attributes the fact that the malware is eight times more than the number of computers since machines can be infected with multiple threats. It looks like MSE is making quite an impact already.

The Microsoft spokesperson confirmed our suspicions that this data was coming from Microsoft SpyNet, the network of Windows Defender and Microsoft Security Essentials users that help determine which programs are classified as malware. "Providing high quality detection capabilities requires that we collect information regarding malware when detected so that we can properly react to deliver the level of PC protection we are promising to customers," he explained. "Users can change the membership level at any time from basic to advance and back however to continue using Microsoft Security Essentials, they need to remain a member of this online community. More information about Microsoft Security Essentials collection and use of information can be found in our privacy statement."

Microsoft also made the effort to show which operating systems MSE is being installed on. Considering Windows 7 has yet to hit general availability (the date is less than one week away), it's surprising to see it in the lead. We can likely attribute this to early adopters: those who are using Windows 7 before it is officially available are more likely to try the first version of another Microsoft product. Microsoft also noted that about one third of Windows 7 machines running MSE are 64-bit, which is even more resistant to malware than 32-bit due to features like Kernel Patch Protection (KPP, informally called PatchGuard) that prevents patching the kernel. Finally, Microsoft also noted that Windows 7 had the fewest number of detections, which the company quickly pointed out follows the trend of less malware on newer operating systems and service packs.

We would normally tell Microsoft not to jump to conclusions so fast (many users haven't had enough time to get Windows 7 properly infected!), but we know Windows Vista is much more secure than Windows XP and this is again reflected in the numbers. Just over half of all detections were on XP while just under a third were on Vista. We would be surprised if Windows 7 didn't end up being more secure than Vista and XP, but we have to say that it's just too early to tell for the moment.

Microsoft Security Essentials was released over two weeks ago and received a preliminary two thumbs up from us. Redmond insists on recommending MSE especially to those who don't have any antimalware software on their computer.

Microsoft only has one week's worth of data to show us for now, but as we've said before, it's going to be a very interesting next few months as we watch the new security package get put through some real-world tests conducted by different groups. We'll keep you posted.